By Rich Loeber,
Part of the job of a security officer is creating, maintaining and testing your disaster recovery plan. A major part of disaster recovery is recreating your computing environment on a completely different system and this always involves data and program restores. You might be one of the fortunate ones that has access to a comprehensive third party save/restore application that automates the disaster recovery restore process for you. If you’re in this group, this post is not for you. But, if you’re a small to medium sized shop that can’t afford (or won’t consider) one of these products, then you’re on your own to create a workable disaster recovery method.
If you fall into this group, then you should consider implementing a LODRUN program to automate your disaster recovery process. LODRUN is an i/OS command that is normally just used by developers of third party software as a method of controlling the installation process for their software packages. But, LODRUN can easily be used to automate your recovery restore process as well.
When you run the LODRUN program, the command calls a process which looks for a *PGM object at the beginning of the tape with the unique name of QINSTAPP. Once found, it will transfer this *PGM object into the special QTEMP library and then call it, passing along the parameters from the LODRUN command which includes the device name of the tape drive being used.
So, for you to have a controlled restore of your backup tape, all you need to do is create a CL program named QINSTAPP with a single parameter for the tape device name. Then, you can use that CL program to do the controlled restore from the tape onto the new system.
A typical off-site backup tape will contain the following items:
1. A backup of the user profiles
2. A backup of the configuration
3. Backups of the user libraries
4. Backups of the IFS objects
You are probably already familiar with exactly how you do backups for your shop. To use the LODRUN method for an automated restore, all you need to do is create a CL program named QINSTAPP that will restore the objects from the backup tape in the same sequence in which they are recorded on the tape.
1. Change your save program to transfer the QINSTAPP *PGM object to QTEMP and then do a SAVOBJ to save it as the very first object on your backup tape.
2. Be sure that you use the *LEAVE option so that the tape is properly positioned after each restore is completed.
3. Be sure to run the RSTAUT command after everything has been restored to get the authorities correct.
4. Use the CHKTAP command at the very end to rewind and/or unload the tape, this will give you better flexibility when it is time to make changes to your program.
5. Add a clear comment to the CL program you use for creating backups that advises any programmer that works on that program to make sure and mirror any changes in your restore program.
6. When you first create the QINSTAPP CL program, have your save program handy so that you get the sequence of events absolutely correct.
When you’re ready to run the restore, all you’ll need to do is mount the tape and issue the LODRUN command. At that point, you custom restore program will take over and give you a quick, complete and controlled restore of your system on your recovery system. If you’d like to see a sample QINSTAPP program, send me an email (firstname.lastname@example.org) and I’ll send you a shell that I recently created.